The UK's referendum on its membership of the EU will be held on 23 JuneYves Herman/Reuters

Fears the City of London would be dealt a major blow should Britain leave the European Union (EU) are exaggerated and a Brexit would be a catalyst for a better Britain, the co-founder of of Hargreaves Lansdown has claimed.

Peter Hargreaves, who set up the FTSE 100 stockbroker with Stephen Lansdown in the 1980s, said leaving the EU would present Britain with the opportunity to become more financially dynamic. "I'm firmly convinced that day – hopefully – we decide to leave, that little bit of insecurity, that little bit of unknown will be an absolute fillip to everyone," Hargreaves told the BBC. "It will be a great incentive for us to go out and prove that it's right."

Hargreaves, who was speaking in a personal capacity, went on to liken a post-Brexit Britain to Singapore in the 1960s, adding leaving the EU should be seen as an inspiration rather than an issue. "When Singapore became independent from Malaysia, that little insecurity that they were no longer part of Malaysia, it was an inspiration," he said. "I honestly think that would be good for us too."

A number of business groups and investment banks have voiced concerns that leaving the 28-country bloc would see Britain, and the City of London in particular, shunned by investors as economic ties with the EU would have to be renegotiated. Hargreaves, however, dismissed the concerns and insisted Britain would still be able to attract foreign investors even if it chose to be outside the EU.

"We raise money for the Russians, we raise money all over the world, for countries that are not in Europe," he said. "They've got to use London. London can raise billions on a few phone calls."

On 14 March, credit rating agency Standard & Poor's (S&P) said in the event of a Brexit, international banks could refocus their European businesses away from Britain, particularly if the UK was no longer part of the passporting arrangement – which allows credit institutions from EU countries to carry out their business in another member state without having to obtain an official authorisation from the relevant regulator.